; TMS320C54x assembly language code
; Block FIR filtering
; Addresses: a4 h, a5 N samples of x, a6 input buffer, a7 output buffer
; Modulo addressing prevents need to reinitialize regs each sample
; Moving filter coefficients from program to data memory is not shown
; Example taken from the C54x Applications Guide, pages 4-3 and 4-4.
firtask:
	ld	#firDP,dp		; initialize data page pointer
	stm	#frameSize-1,brc	; compute 256 outputs
	rptbd	firloop-1
	stm	#N,bk			; FIR circular buffer size
	ld	*ar6+,a			; load input value to accumulator b
	stl	a,*ar4+%		; replace oldest sample with newest
	rptz	a,#(N-1)		; zero accumulator a, do N taps
	mac	*ar4+0%,*ar5+0%,a	; one tap, accumulate in a 
	sth	a,*ar7+			; store y[n]
firloop:	ret